Export STL who to increase scale range
The code snippet you posted is from the ImportSTL class. The ExportSTL class is defined below as follows:

    171    global_scale = FloatProperty(
    172        name="Scale",
    173        min=0.01, max=1000.0,
    174        default=1.0,
    175        )


You can simply change the values, save the file and restart blender like so:

    171    global_scale = FloatProperty(
    172        name="Scale",
    173        min=0.00001, max=1000.0,
    174        default=1.0,
    175        )